The invention relates to an electronic component with a semiconductor composite structure comprising at least one diamond layer.
U.S. Pat. No. 5,117,267 discloses an electronic component which has a semiconductor composite structure. In the known semiconductor composite structure, in order to produce an electronic component, such as for example a transistor or a luminous diode, an n-doped cubic semiconductor layer of boronitride (C-BN) is arranged on one side of a p-doped diamond layer, and a p-doped C-BN layer is arranged on the other flat side of the p-doped diamond layer. These components thus comprise an active p-doped diamond layer, whereby at the transition between the n-doped C-BN layer and the p-doped diamond layer, a discontinuity of band energy levels is formed. In any event, the diamond layers, which are required for depositing electronically useful semiconductor composite structures, are of low crystal quality, relatively difficult to produce and expensive. Furthermore, semiconductor composite structures of this type also have a high resistance.
GB 2,228,949 A discloses a semiconductor composite structure for electronic components in which a diamond layer, which is n-doped with Si, is deposited by means of chemical vapor deposition on an inexpensive silicon substrate. By means of this n-doping of the diamond layer with silicon, the resistance of this semiconductor composite structure is smaller than semiconductor composite structures which have been n-doped as in the past by means of phosphorous and lithium. Nevertheless, the semiconductor composite structure still has a resistance which is too high.
It is therefore an object of the invention to provide a semiconductor composite structure of the type described above, which is characterized by a low resistance.
This object is achieved by the basic electronic component structure according to the invention, in which a doped semiconductor layer is adjacent to an undoped diamond layer. Due to the resulting band discontinuity of the valence band and/or conduction band at the transition between the semiconductor layer and the diamond layer, charge carriers generated optically and/or thermally in the doped semiconductor layer pass into the valence band and/or conduction band of the undoped diamond layer. In the diamond layer, which has a smaller energy gap between the conduction and valence bands, the charge carriers that have flowed out of or been taken up from the C-BN layer (which has a larger energy gap) form at least quasi-free charge carriers. Because they have a low activation energy, the resistance of semiconductor composite structures of this type is relatively small.
Furthermore, because the diamond layers of semiconductor composite structures of this type need not be doped, the associated problem of reproducibility, additional contamination, disturbance points for displacements and the like are at least decreased. Thus, the ionized charge carrier bodies cannot act, or act only to a small extent, as scattering centers for the charge carriers in the active diamond layer. It has further proven to be advantageous that in semiconductor composite structures of this type, n-doping, as well as p-doping, is possible in a simple and inexpensive manner.